Radar directional antenna system



March 29, 1960 R b ET AL 2,931,035,

RADAR DIRECTIONAL ANTENNA SYSTEM Filed Sept. 10, 1955 2 Sheets-Sheet 1 6 I I T25 j 48 2 4.

I l l I J I 7 l5 #3 I 995752534755 s5 s4 53 March 29, 1960 1.. REINHARD ET AL RADAR DIRECTIONAL ANTENNA SYSTEM 2 Sheets-Shem 2 Filed Sept. 10, 1956 3 y 1 3 m 3 H was RADAR DERECTIONAL ANTENNA SYSTEM Application September 16, 1956, Serial No. 608,743

Claims priority, application Switzerland February 22, 1956 20 Claims. (Cl. 343-766) Our invention relates to a radar directional antenna system comprising a tiltable radiator which forms part of a mechanical oscillatory system and is driven to perform a harmonic oscillating motion about a mid-position. The oscillatory motion in such antenna systems, as a rule, has a frequency of a few cycles per second. The tiltable radiator or" the system is either the primary radiator alone, or the reflector operating as a secondary radiator alone, or the combination of primary and secondary radiators. With an oscillating reflector and a stationary primary radiator, the angular amplitude of the oscillating motion is supposed to be about 20 so that the directional radar beam passes through a sector of about 240. When simultaneously imparting to the entire antenna, comprising the primary radiator as Well as the reflector, a scanning motion about an axis prependicular to the tilting axis of the above-mentioned oscillation, a rapid searching movement of the directional beam within a limited angular range of space can be obtained.

In a known directional antenna system of this type,-

the reflector mounted on a tilting shaft forms a mechanical oscillatory system together with two springs acting in mutually opposed directions upon respective arms connected with the tilting axis. The tilting axis is driven through a counter gearing from a reversible electric motor. The motor is switched on and oif by means of an angular transmission member connected with the tilting axis. When the movable assembly reaches a limit position of oscillation, the assembly controls an impulse transmitter which operates through a relay to effect a reversal of current and thus a reversal of the motor running direction. 7

Such a system has all disadvantages inherent in the reversible operation of electric motors, mainly including the occurrence of impact stresses acting upon the mechanical and electrical devices and upon the electric power source and causing increased wear of these devices, as contrasted to the more favorable conditions obtaining with continuous operation. In addition, the above-mentioned system has the further disadvantage that the amplitude of the reflector oscillations may vary under the effect of wind forces.

It is an object of our invention to provide a radar directional antenna system for the above-mentioned purposes which greatly minimizes or eliminates such deficiencies.

To this end and in accordance with one of the features of our invention, the mechanical oscillatory system of whichthe radiator forms part is connected with a continuously operating drive motor through a practically rigid transmission for converting the motor rotation into harmonic oscillation, the connection including a hydraulic damping device of practically infinitely large damping relative to the transmitted driving power, up to an upper limit of the force being transmitted.

The term rigid transmission as used herein is understood to mean a mechanical transmission of the constrained, positive displacement type so that the output rates hatent amplitude or path of motion is always rigidly proportional to the input amplitude or amount of motion. Consequently the provision of a practically rigid connection between'the drive motor and the mechanical oscillatory system secures, within a limited range of forces, a constant amplitude of the oscillatory system independently of any extraneous forces acting upon the oscillating radiator.

The foregoing and more specific objects, advantages and features of our invention will be understood from the embodiment illlustrated on the drawings by way of example and described in the following. In the drawing:

Fig. 1 is a schematic and sectional view, in elevation,

of a complete radar antenna system comprising the driving components and the radiator connected therewith, this radiator consisting in the example of a reflector tiltable in a vertical plane;

Fig. 2 is also a section in elevation, showing, on a larger scale, a portion of Fig. 1 comprising the hydraulic clamping device forming part of the reflector drive; and

Fig. 3 is a schematic view of the system seen from the right of Fig. l.

The illustrated apparatus comprises a housing structure composed of a main housing 1 and two lateral gear housings 2 symmetrically arranged on top of the main housing 1. The housing 1 is hermetically sealed and almost completely filled with oil. Mounted within housing 1 are a drive motor, a transmitting mechanism for translating the rotation of the drive motor into harmonic oscillation, a hydraulic damping device forming part of the drive, and a number of control components, all more fully described below.

The reflector 3 has two carrier rails 4 mounted on a pivot shaft 5 which extends horizontally through the two gear housings 2 and is journaled for oscillatory rotation. Each gear housing 2 has an extension 2'. each extension 2' is a helical compression spring 6 which acts upon a connecting rod 7. A second helical compression spring (not illustrated but identical in type) is mounted within the gear housing 2 and acts upon the same connecting rod from below in the same manner as the spring 6 but in the opposite direction. The connecting rod is articulately joined with an arm 8 rigidly mounted on the reflector pivot shaft 5. Another shaft 9 extends through the two gear housings 2 in parallel relation to shaft 5. Shaft 9 is fixed and carries ball bearings 10 on which respective circular discs 11 are mounted. Each disc 11 has a lateral spur-gear portion 12 in mesh ing engagement with gear segment 13 rigidly fixed to the pivot shaft 5. Mounted on the periphery of the disc 11 are balancing weights 14 so dimensioned as to secure smooth and impact-free oscillation of the entire mechanical oscillatory system comprising all of the masses (3, 4, 8, 13) rotating about the axis of shaft 5, and also the messes (10, 11, 12, 14) rotating in the opposite sense about the axis of shaft 9, as well as the springs acting upon the rod '7.

The electric motor 15, mounted in housing 1, carries on its shaft a spur gear 16 meshing with a spur gear 17 on the shaft of a Worm 18 which meshes with a worm gear :19 on a shaft 19'. Mounted on shaft 19' are two eccentrics 29 located on either side of the worm gear 19,

only one of'the eccentrics 20 being visible in Fig. 1. Theeccentrics 2% act upon respective connecting rods 21 ing 24, a cylinder 25 slidably mounted in housing 24 for longitudinal motion relative thereto, and a double acting piston 26 mounted on piston rod 23 in cylinder 25.

The two cylinder chambers, separated from each other by the piston 26, are closed during normal'operationof Patented Mar. 29, 1960 Located withintion with the space surrounding the damping device.

the apparatus so that the damping elfect is practically infinite. That is, the piston26 is normally in virtually rigid connection with the cylinder 25. Milled intothe top of thecylinder-ZS, on'the outside thereof, is an axially extending spur-gear. rack with which a pinion 28' on a shaft 27' is in meshing engagement. The two ends of shaft 27 protrude laterally into the respective gear housings 2 and carry anotherfpinion, coaxially with pinion. 28 and of'the, same size, which is in meshing engagement. with one of the respective spur-gear circles 12, thus completing the chain of power transmission between the electric motor and the:oscillatory system.

Details of the damping device are apparent from Fig. 2. The cylinder has both sides closed by respective covers or closures 29 which are held in the cylinder by means of respective spring rings 30 and therefore can yield to a limited extent to interior over-pressure. The driving force to be-transmitted by the damping device is limited by means of relief valves responsive to over pressure, through which the two cylinder chambers 31 and 32 on opposite sides of the piston 26 are in communica- The pressure relief valves are disposed Within the piston rod 23. Each piston rod has a bore 33 located in the immediate vicinity of the piston 26 and extending transversely through the piston rod 23 so as to communicate with the adjacent cylinder chamber. From each bore 33, a longitudinal bore 34 extends toward the other end of the piston rod 23. A constricted portion of bore 34 is kept closed by a ball 35 under the pressure of a spring 36. The spring 36 is seated upon the end of a tube 37 placed into the longitudinal bore 34 and fastened thereinby means of a screw sleeve 37'. To make certain that the piston 26 can move from the mid-position without hindrance when one of the relief valves opens, the cylinder chamber then being expanded by such piston movement must likewise be connected with the exterior space. For this purpose, two slide valves are provided which are formed by longitudinal grooves 38 of the piston rod 23 on both sides respectively of the piston 26. In the mid-position of the piston, the longitudinal grooves 38 extend from the outside up to the inner edge of the cylinder cover 29. The grooves have also the effect that the piston, during the stroke following the response of one of the relief valves, is returned back to the mid-position of the cylinder without appreciable counterpressure.

In any position of cylinder 25, the cylinder chambers 31 and 32 communicate through respective openings 39 and 40 in the wall of cylinder 25 with a hollow space 41 or 42 in the stationary housing 24 of the damping device. Separate conduits 43 and 44 lead from the mutually separated spaces 41 and 42 to one of two respective control valves (Fig. l) which are simultaneously operable and are closed in the operating condition of the apparatus but open when the apparatus is inactive. When the control valves, during operation of the apparatus, are open, they interconnect the two hollow spaces 41 and 42 and thus connect the cylinder chambers 31 and 32 with the exterior space of the damping device. Consequently, when the control valves are open, the rigid connection between the piston 26 and the cylinder 25 is eliminated to a large extent so that the oscillator system, when stopping the drive, can continue to freely perform decaying oscillations until it reaches standstill and the reflector 3 has adjusted itself automatically to the midposition of the tilting movement. Such automatic adjustment of the reflector into a given midposition is indispensable if the directional antenna apparatus is to permit a selection of different movements of the directional beam; that is when, aside from the above-described tilting movement of the reflector with a stationary primary radiator as described above with reference. to the illustrated example, another, typeofmovementof theprimary' radiator, such as a cir- 4 cular motion about the symmetry axis of the stationary reflector, is needed.

The above-mentioned two control valves have in common a valve cylinder 45 (Fig. l) to which the conduits 43 and 44 are connected. The cylinder 45 has lateral openings 46 and 47 located opposite the openings of the incoming conduits43 and 44 respectively. The control valves further comprise a valve piston 48 provided with slots 49 and 50'.

The dual control valve is shown in Fig. 1 in theopen position. it is actuated by means of a control piston 51 which is connected with the valve piston 48 and displaceable within a pressure cylinder 52 adjacent to the valve cylinder 45. Movement of the control piston 51 is eflfected in opposition to the force of a return spring 53. The pressure for displacing the control piston 51 is supplied from a small pump 54 stationarily mounted in housing 1 and connected by a pipe 55' with the pressure cylinder 52. The piston 56 of pump 54 is connected through a rod 57 with the bridge member 22 of the crank. drive actuating the damping device as described above.

The reflector 3 can be blocked in the midposition of oscillation by means of a device which is controlled by the valve piston 48'and which comprises a longitudinally movable latch member 58. In the condition of rest of the apparatus, the latch member 58 is forced by a com.- pression spring 59 into latching engagement with a notch 60 in the gear segment 13. The latch member 58 is linked to one arm of a double-armed lever 62 pivoted at 61. The other arm of lever 62 rests upon the upwardly extended end of the valve piston 48. The latter arm of lever 62, during return movement, is further subjected to a damping force produced in a stationary damping cylinder 63 by means of a piston 64. A regulating nozzle permits adjusting the damping force so that the latch member 58 enters into the notch 60 of gear segment 13 only when the oscillatory system is at rest.

The operation of the described apparatus is as follows: At the moment when the electric drive commences its operation, the valve piston 48 is in the position illustrated in Fig. 1, and the oil-filled cylinder chambers 31 and 32 are in communication with the exterior space. Consequently the piston 26 of the drive-damping mechanism at first moves inetfectively in cylinder 25. However, the pump 54 also commences to operate with the effect of gradually lifting the control pitson 51. As soon as the valve piston 48 closes the ports 46 and 47, there may still exist a communication of the then larger cylinder chamber with the outside by way of the one correlated longitudinal groove 38 in the piston rod 23'. However, this communication is discontinued at the moment when the piston 26 next reaches the midposition. Then, the damping efiect is practically infinitely large so that nearly the entire driving'force is transmitted to the cylinder 25. In the meantime, the valve piston 48 has been fully lifted in opposition to the damping force of the damping piston 64 and thus has released the latching device 58, 60 for oscillatory operation of the system.

Since the forces for accelerating the oscillatory system are relatively great, the pressure relief valves will respond during the first eifective strokes of the piston 26, whereafter the piston each time again adjusts itself to its midposition in cylinder 25. However, once the oscillator, system has reached the normal amplitude, the damping device represents a: nearly-rigid. member of. the" driving power transmission, and the amplitude of oscillation of therefiector remains'constant from then on, independently of'extraneous forces as long as these do not-exceed the limit value. given, bythe critical pressurevalue at which thereliet valves will respond.

. The response'of. an over-pressure relief valve during operation of the apparatuszhas the effect of temporarily displacing thepiston26 fiom itszmidposition in cylinder 25. and thus causes atemporary" departure of the'mid position of the. reflector oscillation from the'corrcct value.-

However, this displacement is automatically eliminatedbecause the piston 26 can transmit a force to the cylinder 25 only in the midposition of piston 26 due to the fact that the cylinder chamber then expanding as a result of the piston displacement remains in connection with the exterior space through the longitudinal grooves 38 in piston rod 23 until the piston has reached the midposition.

When stopping the drive, the pump 54 ceases to produce pressure and the control piston 51 moves downward together with the valve piston 48 under the pressure of spring 53. This clears the ports 46 and 47 so that both cylinder chambers of the damping device are now connected with the surrounding space. Consequently the oscillatory system can now freely perform decaying operations and adjust itself into the correct midposition independently of the position occupied by the piston 26 when stopping. Thereafter the spring 59 is efiective upon the latch member 58 in opposition to the damping force of the piston 64 to engage the notch 60 in gear segment 13 thereby locking the reflector 3 in the proper midposition.

Practical experience with radar antenna apparatus as described above has shown that extraneous forces acting upon the reflector, for instance due to wind or icing as well as to slight fluctuations in the rotating speed of the electric drive motor, do not appreciably affect the amplitude of oscillation.

It will be understood by those skilled in the art, upon a study of this disclosure, that our invention permits of various modifications and alterations particularly with respect to the individual components, their design and arrangement, and hence may be embodied in apparatus other than the one specifically illustrated and described, without departing from the essence of our invention and within the scope of the claims annexed hereto.

We claim:

1. A radar directional antenna apparatus providing an oscillatory system, comprising a radar-beam radiator member, means mounting the member for tilting displacement about a tilting axis, a power-driven transmission train to reciprocably tilt the member on said axis, means operatively connected to the tilt axis to resiliently oppose the reciprocation, a rotating motor comprising the power means for said transmission train, a hydraulic motion damping device, said transmission train including a moving element of the damping device, control means for the damping device, the control means normally setting the latter for substantially infinite damping, relative to the driving power of the motor, to provide angular displacement of the radiator member on F said tilt axis in proportion to the input displacement conferred by the motor upon the transmission means, said damping device comprising a reciprocable piston and means providing a housing therefor, fluid outlet means communicating with respective opposite faces of the piston, said control means providing controlled outlet valves for the said fluid outlet means, means for latching the radiator member in mid-position of its tilting displacement when the control means sets the sad outlet valves to open position to permit freedom of motion of the piston of the clamping device so that the motor is not then operably connected by said device to tilt the radiator member, the control means including a device operably connected for movement correlative with that of the reciprocable piston of the clamping device and serving to determine the position of the said outlet valves.

2. A radar directional antenna apparatus providing an oscillatory system, comprising a radar-beam radiator member, means mounting the member for tilting displacement about a tilting axis, a power-driven transmission train to reciprocably tilt the member on said axis, means operatively connected to the tilt axis to resiliently oppose the reciprocation, power means for said transmisi9n train, said transmission train including a hydraulic motion damping device, control means for the clamping device, the control means normally setting the latter for substantially infinite damping, relative to the driving power of the power means, to provide angular displacement of the radiator member on said tilt axis in proportion to the input displacement conferred by the power means upon the transmission means, said damping device comprising a reciprocable piston and housing means providing a chamber therefor, the housing means being connected for reciprocation by the power means to tilt the radiator member, fluid outlet means communicating with respective opposite faces of the piston, said control means providing controlled outlet valves for the said fluid outlet means, means for latching the radiator member in mid-position of its tilting displacement when the control means sets said outlet valves to open position to permit freedom of motion of the piston of the damping device, so that the power means is hot then operably connected by said device to tilt the radiator member, the control means including a device operably connected to the power means to open said valves when the drive of the power means is stopped.

3. A radar directional antenna apparatus providing an oscillatory system, comprising a radar-beam radiator member, means mounting the member for tilting displacement about a tilting axis, a power-driven transmission train to reciprocably tilt the member on said axis, means operatively connected to the tilt axis to resiliently oppose the reciprocation, a rotating motor comprising the power means for said transmission train, a hydraulic motion damping device, said transmission train including a movmotor upon the transmission means, said control means including an automatic device controlled by the motor operation to control the said setting of the damping device and to permit free decaying oscillation of the radiator member when the motor drive is stopped.

4. A radar directional antenna apparatus providing an oscillatory system, comprising a radar-beam radiator member, means mounting the member for tilting displacement about a tilting axis, a power-driven transmission train to reciprocably tilt the member on said axis, means operatively connected to the tilt axis to resiliently oppose the reciprocation, a rotating motor comprising the power means for said transmission train, said transmission train including a hydraulic motion damping device, control means for the damping device, the control means normally setting the latter for substantially infinite damping, relative to the driving power of the motor, to provide angular displacement of the radiator member on said tilt axis in proportion to the input displacement conferred by the motor upon the transmission means, said damping device comprising a reciprocable piston and means providing a housing therefor, the housing being part of the transmission train and being reciprocable by the motor to tilt the radiator member, fluid outlet means communicating with chambers in the housing at respective opposite faces of the piston, said control means providing controlled outlet valves for the fluid outlet means, means for latching the radiator member in mid-position of its tilting displacement when the control means sets said outlet valves to open position to permit freedom of motion of the piston of the damping device so that the motor is not then operably connected by said device to tilt the radiator member, the control means including a device operably connected to the reciprocable piston of the damping device to determine the position of the outlet valves, the apparatus also providing pressure outlet valves operative to communicate the chamhere at opposite faces of the piston of the damping device with the outside of the housing of said piston when the piston departs from its mid-portion in said housin '5. A radar directional antenna apparatus providing an oscillatory system, comprising a radar-beam radiator member, means mounting the member for tilting dis placement about a tilting axis, a power-driven transmission train to reciprocably tilt the member on said axis, means operatively connected to the tilt axis to resiliently oppose the reciprocation, a rotating motor comprising the power means for said transmission train, said transmission train including a hydraulic motion damping device, control means for the clamping device, the control means normally setting the latter for substantially infinite damping, relative to the driving power of the motor, to provide angular displacement of the radiator member on said tilt axis in proportion to the input displacement conferred by the motor upon the transmission means, said clamping device comprising mutually displaceable elements comprising a reciprocable piston and means providing a housingtherefor, fluid outlet means communicating with chambers in the housing at respective opposite faces of the piston, said control means prov'iding controlled outlet valves for the fluid outlet means, means for latching the radiator member in mid-position of its tilting displacement when the control means sets the said outlet valves to open position to permit freedom of motion of the piston of the damping device so that the motor is not then operably connected by said device to tilt the radiator member, the control means including a device operably connected to the reciprocable piston of the damping device to determine the position of the said outlet valves, and over pressure relief valves-for each of said chambers of the clamping device housing, the apparatus also providing pressure outlet valves operative to communicate said chambers with the outside of the damping device housing when the piston of said damping device departs from'its mid-position in the said housin 6. A radar directional antenna apparatus providing an oscillatory system, comprising a radar-beam radiator mem ber, means mounting the member for tilting displacement about a tilting axis, a power-driven transmission train to reciprocaoly tilt the member on said axis, spring means operatively connected to the tilt axis and acting in mutually opposed directions to resiliently oppose the reciprocation, a rotating motor comprising the power means for said transmission train, said transmission train including a hydraulic motion damping device, control means for the damping device, the control means normally setting the later for substanttially infinite damping, relative to the driving power of the motor, to provide angular displacement of the radiator member on said tilt axis in proportion to the input displacerient conferred by the motor upon the transmission means, said damping device comprising a reciprocaole piston and means providing a chamber therefor, fluid outlet means communicating with respective opposite faces of the piston, said control means including a chamber and slide valve and piston member therein providing outlet valves for the fluid outlet mcans, means positioned by the slide valve member for latching the radiator member in mid-position of its tilting displacement when the control means is set to permit freedom of motion of the piston of the damping device so that the motor is not then operably connected by said device to tilt the radiator member, and a fluid pump having a piston operably connected to the reciprocable piston of the damping device and having a pump chamber communicating with a face of the piston member of the control means to control the position thereof.

7. A radar directional antenna apparatus comprising a mechanical oscillatory system, a tiltable radar-beam radiator member forming part of said oscillatory systom and having harmonic oscillatory motion about a given, mid-position, resilient means biasing said member toward said position, a continuously operable drive motor, transmission means connecting said motor with said oscillatory system for imparting said oscillatory motion to said radiator member, said transmission including a hydraulic damping device, control means for determining the damping action of said device, the control means being settable to result in practically infinite damping up to a given maximum limit of the'driving force being transmitted, to provide, when so set, a driving action for tilting of the radiator member in proportion to the input displacement conferred by the motor upon the transmission means, said control means including automatically operated means governed by the operation of the drive'motor to determine the setting of the damping device.

8. A radar directional antenna apparatus comprising a mechanical oscillatory system, a tiltable radar-beam radiator member comprising a reflector forming part of said oscillatory system and having harmonic oscillatory motion, about a given mid-position, of several cycles per second, resilient means biasing said refiectortoward said position, a continuously operable drive motor, a transmission connecting said motor with said oscillatory system for imparting said oscillatory motion to said radi ator member, said transmission including a damping de-- vice, automatic control means governed in accordance with the drive motor operation for determining the damping action of said device, the control means being automatically operated to set the damping device at practically infinite damping up to a given maximum limit of the driving force being transmitted, to provide, when so set, a driving action for tilting of the radiator member in proportion to the input displacement conferred by the drive motor upon the transmission means, said setting at practically infinite damping being operative when the drive motor is in operation.

9. A radar directional antenna apparatus comprising a mechanical oscillatory system, a tiltable radar-beam radiator member forming part of said oscillatory system and having harmonic oscillatory motion, about a given mid-position, of several cycles per second, resilient means biasing said radiator member toward mid-position, a continuously operable drive means, a transmission connecting said drive means with said oscillatory system for imparting said oscillatory motion to said radi-' ator member, said transmission including a damping device, automatic control means governed in accordance with the operation of the drive means for determining the damping action of said device, the control means being automatically operated to set the damping device at practically infinite damping up to a given maximum limit of the driving force being transmitted, to provide,

when so set, a driving action for tilting of the radiator member in proportion to the input displacement conferred by the drive means upon the transmission means, said setting at practically infinite damping being operative when the drive means is in operation, the control means being automatically operated to disengage the damping action of said damping device when the drive means is inoperative, to permit the member to perform freely decaying oscillation into a given mid-position.

10. A radar directional antenna apparatus comprising a mechanical oscillatory system, a tiltable radar-beam radiator member comprising a reflector forming part of said oscillatory system and having harmonic oscillatory motion, about a given mid-position,- of several cycles per second, a continuously operable drive motor, a transmission connecting said motor with said oscillatory system for imparting said oscillatory motion to said radiator member, said transmission including a hydraulic piston and chamber damping device, automatic control means governed in accordance with the operation of the drivev motor for determining'the damping action of said device, the control means including a second piston and chamber device automatically operated to set the damping device at practically infinite damping up to a given 9} maximum limit of the driving force being transmitted, to provide, when so set, a driving action for tilting of the radiator member in proportion to the input displacement conferred by the drive motor upon the transmission means, said setting at practically infinite damping being instituted when the drive motor is in operation, the control means being automatically operated to disengage the damping action of said damping device when the drive motor is stopped to permit the reflector to perform freely decaying oscillation into a given mid-position, the first and second pistons being operatively connected for conjoint operation by the drive motor.

11. A radar directional antenna apparatus comprising a mechanical oscillatory system, a tiltable radarbeam radiator member comprising a reflector forming part of said oscillatory system and having harmonic oscillatory motion, about a given mid-position, of several cycles per second, resilient means biasing said radiator member toward mid-position, a drive means, a transmission connecting said drive means with said oscillatory system for imparting said oscillatory motion to said radiator member, said transmission including a hydraulic damping device, control means for determining the damping action of said device, the control means being settable to result in practically infinite damping up to a given maximum limit of the driving force being transmitted, to provide, when so set, a driving action for tilting of the radiator member in proportion to the input displacement conferred by the drive means upon the transmission means, said control means including automatically operating means governed by the operation of the drive means to determine the setting of the damping device.

12. A radar directional antenna apparatus comprising a mechanical oscillatory system, a tiltable radar-beam radiator member forming part of said oscillatory system and having harmonic oscillatory motion about a given mid-position, a continuously operable drive motor, a transmission connecting said motor with said oscillatory system for imparting said oscillatory motion to said radiator member, said transmission including a hydraulic damping device, control means for determining the damping action of said device, the control means being settable to result in practically infinite damping up to a given maximum limit of the driving force being transmitted, to provide, when so set, a driving action for tilting of the radiator member in proportion to the input displacement conferred by the motor upon the transmission means, said damping device comprising a housing having a space filled with hydraulic medium, a cylinder member axially displaceable within said housing, a double acting piston member axially displaceable in said cylinder and partitioning it into two variable-volume chambers at opposite piston sides respectively, two normally closed pressure relief valves connecting said respective chambers with said housing space, a reciprocating mechanism forming part of said transmission and connecting said motor with one of two members comprising said cylinder member and said piston member, said transmission having means connecting the other of said two members with said oscillatory system.

,13. A radar directional antenna apparatus comprising a mechanical oscillatory system, a tiltable radar-beam radiator member forming part of said oscillatory system and having harmonic oscillatory motion about a given mid-position, a continuously operable drive motor, a transmission connecting said motor with said oscillatory system for imparting said oscillatory motion to said radiator member, said transmission including a hydraulic damping device, control means for determining the damping action of said device, the control means being settable to result in practically infinite damping up to a given maximum limit of the driving force being transmitted, to provide, when so set, a driving action for tilting of the radiator member in proportion to the in- I is put displacement conferred by the motor upon the ease mission means, said damping device comprising a housing having a space filled with hydraulic medium, a cylinder member axially displaceable within said housing, a double acting piston member axially displaceable in said cylinder and partitioning it into two variable-volume chambers at opposite piston sides respectively, two normally closed pressure relief valves connecting said respective chambers with said housing space, a reciprocating mechanism forming part of said transmission and connecting said motor with one of two members comprising said cylinder member and said piston member, said transmission having means connecting the other of said two members with said oscillatory system, said damping device further comprising a piston rod on which said piston member is mounted, said piston rod extending axially through said cylinder member and having two coaxially aligned center bores each connecting one of said respective chambers with said housing space, said pressure relief valves being mounted in said respective bores to normally close said chambers relative to said space.

14. A radar directional antenna apparatus comprising a mechanical oscillatory system, a tiltable radar-beam radiator member forming part of said oscillatory system and having harmonic oscillatory motion about a'given mid-position, a continuously operable drive motor,'a transmission connecting said motor with said oscillatory system for imparting said oscillatory motion to said radiator member, said transmission including a hydraulic damping device, control means for determining the damping action of said device, the control means being settable to result in practically infinite damping up to a given maximum limit of the driving force being transmitted, to provide, when so set, a driving action for tilting of the radiator member in proportion to the input displacement conferred by the motor upon the transmission means, said damping device comprising a housing having a space filled with hydraulic medium, a cylinder member axially displaceable within said housing, a double acting piston member axially displaceable in said cylinder and partitioning it into two variable-volume chambers at opposite piston sides respectively, two normally closed pressure relief valves connecting said respective chambers with said housing space, a reciprocating mechanism forming part of said transmission and connecting said motor with one of two members comprising said cylinder member and said piston member, said transmission having means connecting the other of said two members with said oscillatory system, said damping device including two slide valves closed when said piston member is in mid-position relative to said cylinder member, said slide valves connecting said housing space with the one of said chambers that is expanding when said piston moves away from said mid-position.

15. A radar directional antenna apparatus comprising a mechanical oscillatory system, a tiltable radar-beam radiator member forming part of said oscillatory'system and having harmonic oscillatory motion about a given mid-position, a continuously operable drive motor, a transmission connecting said motor with said oscillatory system for imparting said oscillatory motion to said radiator member, said transmission including a hydraulic damping device, control means for determining the damping action of said device, the control means being settable to result in practically infinite damping up to a given maximum limit of the driving force being transmitted, to provide, when so set, a driving action for tilting of the radiator member in proportion to the input displacement conferred by the motor upon the transmission means, said damping device comprising a housing having a space filled with hydraulic medium, a cylinder member axially displaceable within said housing, a double acting piston member axially displaceable in said cylinder and partitioning it into two variable-volume chambers at opposite piston sides respectively, two normally closed pressure relief valves connecting said respective chambers with said housing space, a reciprocating mech anism forming part of said transmission and connecting said motor with one of two members comprising said cylinder member and said piston member, said trans mission having means connecting the other of said two members with said oscillatory system, said damping device further comprising a piston rod on which the piston member is mounted, said piston rod having two coaxially aligned grooves on opposite piston sides respectively, said cylinder member having two closures means located at opposite ends respectively and traversed by said piston rod, said grooves extending from said housing space up to the inner side of said respective closure means when said piston member is in mid-position, whereby said respective grooves form slide valves which, when said piston member is being displaced from said midposition, connect said housing with the one of said chambers that is expanding at the time. t

16. A radar directional antenna apparatus comprising a mechanical oscillatory system, a tiltable radar beam radiator member forming part of said oscillatory system and having harmonic oscillatory motion about a given mid-position, a continuously operable drive motor, a transmission connecting said motor with said oscillatory system for imparting said oscillatory motion to said radiator member, said transmission including a hydraulic damping device, control means for determining the damping action of said device, the control means being settable to result in practically infinite damping up to a given maximum limit of the driving froce being transmitted, to provide, when so set, a driving action for tilting of the radiator member in proportion to the input displacement conferred by the motor upon the transmission means, said apparatus including an oil-filled housing, said transmission including reciprocating mechanism connecting said motor with said damping device, said motor and said mechanism and also said damping device being mounted within the oil in said housing.

17. A radar directional antenna apparatus comprising a mechanical oscillatory system, a tiltable radar-beam radiator member forming part of said oscillatory system and having harmonic oscillatory motion about a given mid-position, a continuously operable drive motor, a

transmission connecting said motor with said oscillatory system for imparting said oscillatory motion to said radiator member, said transmission including a hydraulic damping device, control means for determining the damping action of said device, the control means being settable to result in practically infinite damping up to a given maxi-mum limit of the driving force being transmitted, to provide, when so set, a driving action for tilting of the radiator member in proportion to the input displacement conferred by the motor upon the transmission means, said damping device comprising a housing having a space filled with hydraulic medium, a cylinder member axially displaceable within said housing, a double acting piston member axially displaceable in said cylinder and partitioning it into two variable-volume chambers at opposite piston sides respectively, two normally closed pressure relief valves connecting said respective chambers with said housing space, a reciprocating mechanism forming part of said transmission and connecting said motor with one of two members comprising said cylinder member and said piston member, said transmission having means connecting the other of said two members with said oscillatory system, the apparatus further comprising two control valves which are closed when said transmission is in driving operation and are open when said transmission is at rest, said control valves, when open, connecting both of said chambers with said housing space. I

18. A radar directional antenna apparatus comprising a mechanical oscillatory system, a tiltable radar-beam radiator member forming part of said oscillatory system and having harmonic oscillatory motion about a given mid-position, resilient means biasing said member toward said position, a continuously operable drivetmotor, transmission means connecting said motor with said oscillatory system for imparting said oscillatory motion to said radiator member, said transmission including a hydraulic damping device, control means for determining the damping action of said device, the control means being scttable to result in practically infinite damping up to a given maximum limit of the driving force being transmitted, to provide, when so set, a driving action for tilting of the radiator member in proportion to the input displacement conferred by the motor upon the transmission means, said control means including automatically operated means governed by the operation of the drive motor to determine the setting of the damping device, the damping device having overpressure release means for limiting the maximum force transmitted by the motor to the radiator member.

19. The apparatus defined in claim 9, the damping device having over-pressure release means for limiting the maximum force transmitted by the drive means to the radiator member.

20. A radar directional antenna apparatus comprising a mechanical oscillatory system,- a tiltable radar-beam radiator member forming part of said oscillatory system and having harmonic oscillatory motion, about a given mid-position, resilient means biasing the member toward said mid-position, a drive means, a transmission connecting said drive means with said oscillatory system for imparting said oscillatory motion to said radiator member, said transmission consisting of rigid members and a variable driving force transmitting device, automatic control means governed by the operation of the drive means for determining the driving force transmitting action of said device, the control means being automatically operated to set the device to transmit force up to a given maximum limit of the driving force being applied by the drive means, to provide, when so set, a driving action for tilting of the radiator member in proportion to the input displacement conferred by the drive means upon the transmission means, said setting being instituted when the drive means is in operation, the control means being automatically operated to set the device for minimum driving force transmitting action when the drive means is inoperative, to permit the member to perform freely decaying oscillation into said given mid-position.

References Cited in the file of this patent FOREIGN PATENTS 7 733,593 Great Britain July 13, 1955 ere 

